Showing papers in "Chemical Engineering Science in 1969"

TL;DR: In this paper, the authors proposed a theory of the thinning of a liquid film between two touching bubbles, which predicts the bubble thinning to occur in two stages, i.e., the first stage is an extremely rapid thinning down to a quasi-equilibrium thickness, which is calculated by the equation: the second stage is the further thinning up to the rupture and the time required for the overall coalescence time.

TL;DR: In this paper, a new model for catalytic reaction in fluidized beds is developed based on multiple bubbles of varying sizes with interchange of gas taking place between the bubble phase and the emulsion phase.

TL;DR: In this paper, a model based on two step mechanism of bubble formation is proposed to explain the discrepancies existing in the literature and data have been collected over a wide range of variables to test the model.

TL;DR: In this paper, residence time distributions in columns under trickle-flow conditions have been measured with the injection of a tracer, and the results indicated the occurrence of two different elementary mechanisms causing a spread in residence time, viz. an eddy diffusion process and mass exchange with stagnant areas.

TL;DR: In this article, it is suggested that atomization results from a Kelvin-Helmholtz instability whereby the destabilizing force is the pressure variation caused by the compression of the air streamlines at the crests of wavelets.

TL;DR: Bubble growth in constant and time-dependent pressure fields has been formulated taking into account not only the effects of surface tension, inertia of liquid, heat conduction in the liquid, but also the effects that nonequilibrium at the liquid-vapor interface, and the varying density of the vapor bubble as discussed by the authors.

TL;DR: The principle of corresponding states is a sound but limited principle from which to predict the thermodynamic properties of pure fluids as discussed by the authors, and van der Waals's approximation has been extended to cover wide classes of fluids and their mixtures.

TL;DR: In this article, an expression analytique regoureuse de la distribution des temps de sejour dans un reacteur semi-infini a ecoulement piston avec dispersion axiale and echange de matiere avec des zones stagnantes est etablie.

TL;DR: In this article, air bubbles were formed from single horizontal orifices submerged in liquids whose viscosity varied from 1·0 to 600 cPs and surface tension from 37 to 72 dyn/cm.

TL;DR: In this paper, an electroresistivity probe was used to determine point properties of an air-fluidized bed of conducting coke particles, which contained two electrodes, one vertically above the other and separated by a known distance.

TL;DR: In this article, a modified Wilke-Chang type equation was used to predict the diffusion data over the entire solvent mixture concentration range using only diffusion data of the solute in each of the pure solvents and viscosity data of mixtures.

TL;DR: In this paper, the problem of gas absorption accompanied by a fast chemical reaction, in a slurry containing sparingly soluble fine particles, is considered, and analytical equations are derived, which predict the effect of simultaneous solid dissolution in the liquid film on the specific rate of absorption.

TL;DR: In this paper, the analogy between the stirred tank reactor and the catalyst particle is used to introduce some of the recent techniques of stability analysis in as simple a way as possible, and the relationship between various classes of criteria for uniqueness and stability is developed and interpretations of the less obvious criteria are given.

TL;DR: In this article, the generalized two-stage model of bubble formation, taking the variation of gas flow rate with time into account, has been derived and the results obtained under intermediate conditions have been quantitatively explained on the basis of these equations.

TL;DR: In this article, simple transfer function models of chemical plant can be reduced to simple models using the method of moments, and three parameters of the simple model are obtained by matching the first three moments of the impulse response of the complex and simple models.

TL;DR: In this paper, the authors consider two aspects of the behaviour of freely bubbling fluidised beds: 1) The rising velocity of bubbles in a fluidised bed has been found to be greater for a swarm of bubbles than for a bubble in isolation, which appears to be caused primarily by the acceleration of overtaking bubbles during the coalescence process.

TL;DR: In this paper, the particle transport mechanism operating during the filtration of dilute suspensions through deep granular beds has been considered on a dimensionless unit cell basis, and it has been shown that the mechanism can be completely described by parameters representing the diffusional, gravitational, interception and impaction mechanism and by the Reynolds Number.

TL;DR: Potential flow theory is used to describe the flow of gas from the chamber beneath a one-holed perforated plate into an expanding, rising, spherical bubble forming at the orifice.

TL;DR: In this paper, exact solutions of the Stokes equations were derived for the case of two unequal spheres slowly rotating or translating perpendicular to their line of centers in a quiescent, unbounded viscous fluid, following Wakiya.

TL;DR: In this paper, the problem of optimization of the balance measurements in complicated chemical engineering systems is addressed, on the basis of application of the calculus of observations the rules are derived for the classification of the measured and unmeasured streams according to their topological properties in the balance scheme.

TL;DR: In this paper, a stochastical model is developed quantitatively describing the influence of catalytic dilution on isothermic kinetic measurements and a dilution criterion is introduced which makes it possible to determine the allowable degree of dilution and the minimum amount of catalyst required.

TL;DR: In this paper, a partial differential equation governing the variation in shape of the draining film with time has been obtained by considering the effect of the pressure gradient, due to viscous flow and gravity, on the deformable fluid-liquid interface.

TL;DR: In this paper, the maximum bed height of a fluidized bed in slug flow is given by the equation H max /H 0 = 1 + ( U − U 0 /0·35 √ ( gD ) where H is height, U is superficial gas velocity, g is gravitational acceleration, D is bed diameter and the subscript 0 refers to minimum fluidization.

TL;DR: In this article, it was shown that a shape derived from a cycloid yields simpler equations describing the assumed flow pattern, than the corresponding equations for a sphere, and the results are quoted which fall outside the range of applicability of the simpler penetration theory.

TL;DR: In this article, the dependence of the complex viscosity of four viscoelastic fluids (three polymer solutions and one polymer melt) on strain amplitude has been studied for large amplitude oscillatory motion using a Weissenberg Rheogoniometer.

TL;DR: In this paper, the authors extended the analysis of reactor kinetics in terms of residence time distributions to unsteady stirred tank reactors and treated them as cyclic or cyclic reactors within the same theoretical framework as steady, continuous flow reactors.

TL;DR: In this article, a method for solving parabolic PDE by means of interpolation of the differential operators in two dimensions is described, which is shown to be highly economical and very stable in comparison with the conventional Crank-Nicolson method.

TL;DR: Least-squares methods for the estimation of Peclet number and mean flow-through time for dispersive flow processes are given in this paper, which are less sensitive to errors occurring in measurement of tracer concentration than are methods involving variance computation.

TL;DR: In this article, the identification of parameters in partial differential equations from experimental output data is investigated and a steep descent algorithm is derived based on minimizing the difference between the experimentally observed output and that predicted by the model.

TL;DR: In this paper, the stability of the gas-liquid interface has been examined using a linearized small-perturbation technique, and the critical gas velocity required to cause unstable waves has been calculated.